I'll echo Mark that the thing that works the best for me first is to crank up the voltage, the gas feed, and the wire feed. I listen for rapidly sizzling bacon and not for slowly sputtering bacon sounds! Man I get hungry when I weld!!!
Some other special tricks and/or special tools I use really help and I'll share some here but they all dependon access to the spot from the other side. First, take a thick copper pipe, split it down the center, fold it out flat, use it
under the spot you are welding and instead of welding the spot upside down, weld it from up above, soooooo much easier. Since weld wont stick to copper, you can fill holes, stich seems and even add metal to any spot you want without ever having it fall through in a melted molten mass.
The second special tool I made from one of those reachable and swivel-able inspection mirrors that has the little one inch inspection mirror...use a tin snip or somthing to just snip the folded over metal ring that holds the mirror in place, pop the mirror out and put a penny in there and then fold that metal ring back over the edge of the penny just like the edge of the mirror, now, feed it up and under the spot that you were going to weld upside down and instead weld it from up above!
All these things help but again they all depend on getting access to the spot from the other side. If you cannot do that, like Mark wrote, crank everything up and make that little piggy sizzle!!! HTH Good Luck.
